KR20220054637A - P matrix for EHT - Google Patents

Abstract

Methods and apparatus are provided. In an example aspect, a method is provided for transmitting a multicarrier symbol comprising a plurality of subcarriers simultaneously from a plurality of antennas. Each subcarrier is associated with a respective orthogonal matrix. The method includes transmitting symbols from the plurality of antennas, such that, for each antenna, a symbol transmitted from each subcarrier is multiplied by an element in each row of a matrix associated with the subcarrier, wherein the row is related to the antenna. The matrix is selected such that, from each antenna, symbols transmitted from at least one subcarrier are multiplied by a non-zero element, and symbols transmitted from at least one other subcarrier are multiplied by a zero element.

Description

P matrix for EHT

Embodiments of the present disclosure relate to transmitting a symbol, e.g., comprising a plurality of subcarriers from a plurality of antennas.

Advanced antenna systems can be used to significantly improve the performance of wireless communication systems in both uplink (UL) and downlink (DL) directions. For example, an advanced antenna may transmit a channel to improve reliability and/or throughput of transmission, for example, by transmitting using multiple spatial streams (also referred to as space time streams). offers the possibility of using the spatial domain of

For example, the 802.11-16 standard specifies a set of matrices (often called P matrices), where rows (and columns) are orthogonal cover codes for channel and pilot estimation when using one or more space-time streams. Specifies the set of orthogonal vectors to be employed (eg, multiple input multiple output (MIMO) operation). The rows or columns of these P matrices can be applied to pilots embedded within data symbols and long training fields (LTFs) when transmitted.

를 생성한다:When the 802.11 system operates in Multiple-Input Multiple-Output (MIMO) mode (eg, single-user SU-MIMO or multi-user MU-MIMO), the number of Long Training Fields (LTFs) N _LTF is the physical included in the layer preamble. A receiver with N _RX estimates the frequency domain channel matrix H _k corresponding to subcarrier k as

creates:

는 k번째 서브캐리어 및 n번째 LTE 심볼에 대응하는 수신된 신호 벡터

을 수집하는 디멘전 N_RX ×N_LTE의 매트릭스, LTF_k는 k번째 서브캐리어에 대응하는 주파수 도메인 LTF 심볼이다.where p is the P matrix,

is the received signal vector corresponding to the k-th subcarrier and the n-th LTE symbol

A matrix of dimensions N _RX × N _LTE that collects LTF _k is a frequency domain LTF symbol corresponding to the k-th subcarrier.

One aspect of the present disclosure provides a method of transmitting a multicarrier symbol including a plurality of subcarriers simultaneously from a plurality of antennas. Each subcarrier is associated with a respective orthogonal matrix. The method includes transmitting symbols from the plurality of antennas, such that, for each antenna, a symbol transmitted from each subcarrier is multiplied by an element in each row of a matrix associated with the subcarrier, wherein the row is related to the antenna. The matrix is selected such that, from each antenna, symbols transmitted from at least one subcarrier are multiplied by a non-zero element, and symbols transmitted from at least one other subcarrier are multiplied by a zero element.

Another aspect of the present disclosure provides a method of transmitting a multicarrier symbol including a plurality of subcarriers simultaneously from a plurality of antennas. Each subcarrier is associated with a respective orthogonal matrix. The method includes transmitting symbols from the plurality of antennas, such that, for each antenna, a symbol transmitted from each subcarrier is multiplied by an element in each column of a matrix associated with the subcarrier, wherein a row is related to the antenna. The matrix is selected such that, from each antenna, symbols transmitted from at least one subcarrier are multiplied by a non-zero element, and symbols transmitted from at least one other subcarrier are multiplied by a zero element.

Another aspect of the present disclosure provides an apparatus for transmitting a multicarrier symbol including a plurality of subcarriers simultaneously from a plurality of antennas. Each subcarrier is associated with a respective orthogonal matrix. The apparatus includes a processor and a memory. The memory includes instructions executable by the processing circuitry to enable the apparatus to transmit symbols from the plurality of antennas, such that, for each antenna, each of the matrix associated with the subcarrier contains, for each antenna, a symbol transmitted from each subcarrier. Let the elements of the row of n be multiplied, where the row is associated with the antenna. The matrix is selected such that, from each antenna, symbols transmitted from at least one subcarrier are multiplied by a non-zero element, and symbols transmitted from at least one other subcarrier are multiplied by a zero element.

Another aspect of the present disclosure provides an apparatus for transmitting a multicarrier symbol including a plurality of subcarriers simultaneously from a plurality of antennas. Each subcarrier is associated with a respective orthogonal matrix. The device may include a processor and memory. The memory includes instructions executable by the processing circuitry to enable the apparatus to transmit symbols from the plurality of antennas, such that, for each antenna, each of the matrix associated with the subcarrier contains, for each antenna, a symbol transmitted from each subcarrier. Let the elements of the column of to be multiplied, where the row is associated with the antenna. The matrix is selected such that, from each antenna, symbols transmitted from at least one subcarrier are multiplied by a non-zero element, and symbols transmitted from at least one other subcarrier are multiplied by a zero element.

A further aspect of the present disclosure provides an apparatus for transmitting a multicarrier symbol including a plurality of subcarriers simultaneously from a plurality of antennas. Each subcarrier is associated with a respective orthogonal matrix. The apparatus is operable to transmit symbols from the plurality of antennas, such that, for each antenna, a symbol transmitted from each subcarrier is multiplied by an element in each row of a matrix associated with the subcarrier, wherein the row is related to the antenna. The matrix is selected such that, from each antenna, symbols transmitted from at least one subcarrier are multiplied by a non-zero element, and symbols transmitted from at least one other subcarrier are multiplied by a zero element.

Another aspect of the present disclosure provides an apparatus for transmitting a multicarrier symbol including a plurality of subcarriers simultaneously from a plurality of antennas. Each subcarrier is associated with a respective orthogonal matrix. The apparatus is operable to transmit symbols from the plurality of antennas, such that, for each antenna, a symbol transmitted from each subcarrier is multiplied by an element in each column of a matrix associated with the subcarrier, wherein: is related to the antenna. The matrix is selected such that, from each antenna, symbols transmitted from at least one subcarrier are multiplied by a non-zero element, and symbols transmitted from at least one other subcarrier are multiplied by a zero element.

For a better understanding of the present disclosure, and to more clearly indicate how examples may be carried out effectively, reference is made, by way of example only, to the following drawings:
1 shows an example of a conference matrix of order n = 10;
2 shows an example of a conference matrix of order n = 14;
3 shows an example of a P matrix of order n = 2;
4 shows an example of a P matrix of order n = 8;
5A is a flowchart of an example of a method for transmitting a multicarrier symbol;
5B is a flowchart of an example of a method for transmitting a multicarrier symbol;
6 shows an example of an orthogonal (±1, 0)-matrix of order n = 16;
7 shows an example of a conference matrix of order n = 6;
8 shows an example of an orthogonal (±1, 0)-matrix of order n = 12;
9 shows an example of a permutation matrix and a P matrix of order n = 16;
10 shows an example of a substitution matrix and a P matrix of order n = 12;
11 shows an example of a substitution matrix and a P matrix of order n = 10;
12 shows an example of a butterfly diagram corresponding to a product by a Hadamard matrix of order n = 16;
Fig. 13 shows an example of a butterfly diagram corresponding to a product by a matrix shown in Fig. 6;
14 is an exemplary schematic apparatus for transmitting multicarrier symbols;
15 is an exemplary schematic apparatus for transmitting a multicarrier symbol.

Certain details are set forth below, such as specific embodiments or examples, for purposes of extension and not limitation. One of ordinary skill in the art will understand that other embodiments may be employed apart from these specific details. In some instances, detailed descriptions of well-known methods, nodes, interfaces, circuits, and apparatuses are omitted as they may unnecessarily obscure the description. One of ordinary skill in the art will appreciate that the functions described may be implemented using hardware circuitry (eg analog and/or distributed logic gates interconnected to perform a particular function, ASIC, PLA, etc.) and/or one or more digital microprocessors or general purpose It will be appreciated that it may be implemented on one or more nodes using software programs and data in conjunction with a computer. The nodes communicating using the air interface also have suitable radio communication circuitry. Moreover, where appropriate, the present technology may reside in some form of computer readable memory, such as a solid state memory, magnetic disk or optical disk, comprising a suitable set of computer instructions that cause a processor to perform the techniques described in this disclosure. It is further contemplated as being implemented in its entirety.

Hardware implementations include, but are not limited to, application specific integrated circuit (ASIC)(s) and/or field programmable gate array (FPGA)(s) and a state machine capable of performing these functions (where appropriate). , digital signal processor (DSP) hardware, reduced instruction set processors, hardware (eg, digital or analog) circuitry, without limitation.

Examples of this disclosure use certain types of orthogonal matrices. The following is a review of some relevant regulations and characteristics. A (±1)-matrix is a matrix whose entries are constrained to the values {-1, +1}. Likewise, the (±1, 0)-matrix has all its entries in the set {-1, +1, 0}. A square matrix M of n×n is an orthogonal matrix if M·M ^H =αI _n . Here, the superscript (.) ^H is a Hermitian matrix transpose, I _n is an identity matrix (identity matrix) of dimension n×n, and α is a positive constant. M can be said to have order n. If M is an orthogonal (±1)-matrix of order n, then n is 1, 2, or even divisible by 4 (i.e., n = 1, 2, 4, 8, 12, 16, ... )am. Consequently, there is a (±1)-matrix of orders 10 and 14. A so-called conference matrix or C-matrix of order n is an orthogonal (±1, 0)-matrix with zeros along the diagonal, all other elements being ±1. A conference matrix is known to exist for orders 10 and 14, and it can be seen that an orthogonal (±1, 0)-matrix of order n cannot have less than n zeros.

(±1) - It can be verified that the orthogonality property of the matrix is preserved by the following operation.

Action 1: Column or row negation.

Operation 2: Permutation (ie swapping) of any two rows or two columns.

Extremely High Throughput (EHT) has been proposed as an enhancement of the IEEE 802.11 standard. In particular, the EHT can provide up to 16 space-time streams. Therefore, we are interested in a P matrix of order 9≤n≤16.

EHT also proposes multi-link operation as well as increasing the channel bandwidth to 320 MHz. With multi-link, the total aggregated bandwidth using multiple channels can exceed 1 GHz. Since the subcarrier spacing is 78.125 kHz, this means we may need to estimate approximately 12800 channel matrix, and since each channel matrix estimate requires a product of two matrices, it is approximately 12800 * 16 at the receiver to estimate the channel. = 204800 P matrix-vector multiplication may become necessary. For MU-MIMO, 802.11ac/ax receivers often estimate channels for all transmitted spatial streams in order to perform cancellation of inter-stream interference. This means that a receiver with N _RX receive antennas will need to perform N _RX times the product of the full P matrix with the vector of received samples. That is, even a station with a small number of receive antennas may need to perform many P matrix-vector multiplications.

A simple way to design a new P matrix is to use a DFT matrix. However, IEEE 802.11 has a preferred P matrix, typically consisting of only +1's and -1's, as this reduces computational complexity and/or memory usage at both the transmitter and receiver, and is efficient as only addition is required. Enables hardware implementation. For example, for 3 or 7 space time streams, the 802.11 standard utilizes a P matrix of dimensions 3x4 and 7x8, respectively, which, in fact, is (±1) of orders 4 and 8, although some overhead is introduced. )-P is a sub-matrix of the matrix. In practice, smaller 3x3 and 7x7 DFT matrices may be suitable, but not (±1)-P matrices.

Therefore, we find a P matrix of dimension 9 ≤ n ≤ 16 that supports low complexity transmitter and/or receiver implementations. Traditionally, IEEE 802.11 has only standardized P matrices of even (even) orders, so a particular example of the present disclosure relates to the case of n=10,12,14,16. A P matrix of odd (odd) order can be generated from a P matrix of even order by removing one or more rows. For n=10, 14, it is impossible to find an orthogonal (±1)-matrix, but it is possible to find an orthogonal (±1,0)-matrix. For N=12, 16, it is impossible to find an orthogonal (±1)-matrix, since multiplication by zero does not need to be performed, so there can be significant complexity reduction at the receiver, but (±1,0)- It may be preferred to use a matrix.

Related to employing the orthogonal (±1, 0)-matrix as the P matrix, since a 0 in the (m, k) entry in the P matrix means that the mth transmitter chain will be muted for the time period corresponding to the kth LTF The problem is that the total transmit power is reduced with respect to the maximum possible output power.

An example of this disclosure aims at the use of an orthogonal (±1, 0)-matrix as a P matrix, and provides a method for avoiding the reduction in transmitter power associated with the presence of (0's) of zeros in the P matrix. In general, examples of the present disclosure suggest applying different P matrices for different subcarriers. The P matrix may be selected in some examples based on two criteria.

1) For every transmitter chain and every LTF, its associated P matrix has a non-zero entry in the columns and rows indicated by the transmitter chain and the LTF.

2) The various P matrices may all be related to each other and/or to the base P matrix. For example, the result of the multiplication of a vector by a given P matrix can be computed by multiplying the vector by a base P matrix, followed by application of an operation with negligible complexity.

The first criterion may ensure that the transmitter chain is not muted during the transmission of the LTF. By scaling the signal properly, the maximum output power can be used in any TX chain. The second criterion may ensure that there is no need to have circuitry or software implementing the multiplication by more than one P matrix.

Thus, an example of this publication proposes an orthogonal cover code that IEEE 802.11 can support from 9 to 16 space time streams. The example proposed orthogonal cover code is specified in terms of a (±1,0)-matrix that supports the implementation of an efficient channel estimation algorithm at the receiver. Examples are provided showing the computational complexity advantageous when compared to other efficient algorithms such as the Hadamard transform and the fast Fourier transform.

An example of this exposure suggests utilizing the (±1,0)-matrix as the P matrix. It may be desirable to utilize as a P matrix orthogonal (±1)-matrix of orders n=10 and n=14, but such a matrix does not exist. An alternative could be to employ an orthogonal (±1,0)-matrix, for example, as a P matrix, such as a conference matrix.

1 shows an example of a conference matrix of order n=10. 2 shows an example of a conference matrix of order n=14. These matrices are referred to below as P ₁₀ and P ₁₄ , respectively. 1 and 2 , a minus sign (-) represents the value −1 while a plus sign (+) represents the value +1. In another example, the minus sign and the plus sign represent predetermined negative and positive values, respectively, and/or may represent predetermined complex values (including unit-sized complex values). A zero (0) in the matrix represents the value zero.

Moreover, although it is known that (±1)-matrices of order n = 12 and n = 16 exist and fast matrix multiplication algorithms are available, reduction in cost, silicon area, power consumption and/or in the transmitter and/or receiver It may be desirable to design a P matrix with much lower matrix product complexity to support savings in computation time. One way to achieve this is to employ the (±1,0)-matrix as the P matrix for orders n=12 and n=16.

The IEEE 802.11-16 standard specifies P matrices P ₂ and P ₈ of orders 2 and 8 respectively, which can be used to derive a higher order P matrix. These matrices 300 and 400 are shown in Figs. 3 and 4, respectively.

5A is a flow diagram of an example of a method 500 for transmitting a multicarrier symbol. A multicarrier symbol includes a plurality of subcarriers, and the symbol is transmitted simultaneously from a plurality of antennas. Each subcarrier is associated with a respective orthogonal matrix. For example, there are at least two different orthogonal matrices.

The method 500 includes, at step 502, transmitting a symbol from the plurality of antennas, for each antenna, a symbol transmitted from each subcarrier is multiplied by an element in each row of a matrix associated with the subcarrier. , where the row is associated with the antenna. The matrix is selected such that, from each antenna, symbols transmitted from at least one subcarrier are multiplied by a non-zero element, and symbols transmitted from at least one other subcarrier are multiplied by a zero element. Thus, for example, for a symbol transmitted simultaneously from multiple antennas, at least one subcarrier from each antenna is multiplied by a zero element, thereby reducing complexity at the transmitter and/or receiver while reducing the complexity at least from each antenna. One subcarrier is multiplied by a non-zero element, allowing the full power to be transmitted from each antenna (e.g., increasing the power for non-zero subcarriers, some subcarriers multiplied by zero) .

In some examples of method 500, for each subcarrier, the symbol transmitted from each antenna is multiplied by each element of a column of the matrix associated with the subcarrier. In some examples, for each subcarrier, the symbol transmitted from each antenna is multiplied by another element of a column of the matrix associated with the subcarrier.

5B is a flow diagram of an example of a method 510 for transmitting a multicarrier symbol. A multicarrier symbol includes a plurality of subcarriers, and the symbol is transmitted simultaneously from a plurality of antennas. Each subcarrier is associated with a respective orthogonal matrix. For example, there are at least two different orthogonal matrices.

The method 510 includes, at step 512, transmitting a symbol from the plurality of antennas, for each antenna, a symbol transmitted from each subcarrier is multiplied by an element in each column of a matrix associated with the subcarrier. , where a column is associated with an antenna. The matrix is selected such that, from each antenna, symbols transmitted from at least one subcarrier are multiplied by a non-zero element, and symbols transmitted from at least one other subcarrier are multiplied by a zero element. Thus, for example, for symbols transmitted simultaneously from multiple antennas, at least one subcarrier from each antenna is multiplied by a zero element, thereby reducing complexity at the transmitter and/or receiver while reducing the complexity at least from each antenna. One subcarrier is multiplied by a non-zero element, allowing the full power to be transmitted from each antenna (e.g., increasing the power for non-zero subcarriers, some subcarriers multiplied by zero) .

In some examples of method 510, for each subcarrier, the symbol transmitted from each antenna is multiplied by each element of the row of the matrix associated with the subcarrier. In some examples, for each subcarrier, the symbol transmitted from each antenna is multiplied by another element of the row of the matrix associated with the subcarrier.

Examples and forms disclosed herein suitable for both method 500 and method 510 may be made applicable.

In some examples, a matrix associated with each subcarrier may be obtained by multiplying a permutation matrix by an orthogonal base matrix or a matrix associated with at least one other subcarrier. In some examples, the matrix is obtained in this way, while in other examples, it is merely the relationship between the matrices, and the matrix is obtained in any suitable manner as described below, for example a circular shift or can be obtained from reordering.

I₂에 따라서 생성될 수 있고, 여기서,

는 크로네커(Kronecker) 매트릭스 프로덕트를 나타낸다. 이 매트릭스(600)는 도 6에 도시된다. 차수 12의 구조화된, 직교 (±1,0)-매트릭스 P₁₂는 도 3에 나타낸 매트릭스 P₂(300) 및 공식 P₁₂

U₆ P12에 의해서 도 7에 나타낸 컨퍼런스 매트릭스(700) U₆으로부터 생성될 수 있다. 이 매트릭스 P₁₂(800)는 도 8에 나타낸다.In one example, a highly structured orthogonal (±1,0)-matrix P ₁₆ of order 16 is given by the formula P ₁₆ =P ₈

can be generated according to I ₂ , wherein

denotes a Kronecker matrix product. This matrix 600 is shown in FIG. 6 . The structured, orthogonal (±1,0)-matrix P ₁₂ of order 12 is the matrix P ₂ (300) and formula P ₁₂ shown in FIG. 3 .

It may be generated from the conference matrix 700 U ₆ shown in FIG. 7 by U ₆ P12. This matrix P ₁₂ ( 800 ) is shown in FIG. 8 .

In some examples of this disclosure, an orthogonal (±1,0)-matrix is employed as the P matrix. This happens when employing the orthogonal (±1,0)-matrix as the P matrix, since a zero in the entry (m, k) of the P matrix means that the mth transmitter chain is muted for the time period corresponding to the kth LTF. The problem is that the total transmit power is reduced with respect to the maximum possible output power. To solve this problem, it is proposed to apply a subcarrier-specific P matrix. That is, different P matrices may be applied to different subcarriers. In a particular example, for a given transmitter chain m and a given LTF symbol k, its corresponding entries for m and k (e.g. in the mth row and kth column for a particular example arrangement of elements in a matrix) There is at least one P matrix in which entry) is non-zero. This ensures that the transmitter chain is not muted during the transmission of the LTF. Moreover, in such a way that a matrix product by a given P matrix can be computed, for example, from the calculation of a matrix product by a base matrix, the base P matrix (which, in some examples, is the P associated with one of the subcarriers). It is proposed to derive all P matrices from This may ensure that, for example, software units and/or circuits employed for calculating the product of a base matrix by vectors can be reused.

One way to generate a new P matrix from a base P matrix is to multiply the base P matrix by a permutation matrix. Briefly, a permutation is a reordering of the rows and/or columns of a matrix of a matrix. In one example, a permutation matrix G of order n is a (1,0)-matrix with the property that each column and each row contains exactly one element with the value 1 while the remaining entries are zero. A first example of a permutation matrix is a time reversal matrix with an element of value 1 along the anti-diagonal and element of value 0 (ie, zeros) everywhere else. A second example of a permutation matrix is a circular shift matrix. Note that the circular shift is a linear operation and therefore can be described in terms of a matrix. A circular shift by one step can be described by a matrix C _n of order n with zeros I, except in the last element of the first row in the sub-diagonal, where C n is one (ie, all entries in C _n are zero, except C _n (i+1,i)=1,C _n (1,n)=1). With this indication, the circular shift by k steps C _n ^(k) is given by:

이다. 또한, 매트릭스 G·P_n와 수신된 샘플의 벡터

의 프로덕트(곱)은

이다. 그러므로, 일부 예에 있어서, 기본 매트릭스에 의한 벡터의 프로덕트

이 계산될 수 있고, 그 다음, 특정 매트릭스에 의한 벡터의 프로덕트로서 동일한 결과를 제공하기 위해서, 결과는 재순서화된다(여기서, 특정 매트릭스는 기본 매트릭스와 치환 매트릭스의 프로덕트이다). Also note that there is periodicity: G _n ^(n+k) =G _n ^(k) . That is, applying n consecutive one-step circular shifts to length n results in an original vector. A given substitution matrix G has the property of G·G ^T =I _n . Therefore, if P _n is an orthogonal matrix of order n and G is an orthogonal matrix of the same order, then G·P _n is also an orthogonal matrix

am. Also, the matrix G·P _n and the vector of received samples

The product (product) of

am. Therefore, in some examples, the product of a vector by a base matrix

can be computed, and then the result is reordered (where the particular matrix is the product of the base matrix and the permutation matrix) to give the same result as the product of the vector by a particular matrix.

In some examples, all matrices are different, but in other examples there may be fewer other matrices than the number of subcarriers, for example at least two different matrices. For example, a first set of subcarriers is associated with a first matrix and a second subset of subcarriers different from the first subset is associated with a second matrix different from the first subset. In another example, there may be another subset(s) of subcarriers, each associated with another, different matrix.

For a specific example, consider the case of order n = 16 (eg, there are 16 antennas). The matrix P ₁₆ 600 shown in FIG. 9 may be selected as the base matrix, and the permutation matrix G may be a time reversal matrix. The P matrix P ^(k) for a given integer k can be defined as:

Moreover, the P matrix P ^(k) may relate to the number of subcarriers k (eg, subcarriers with frequency (kΔf+F _c ), where Δf is the subcarrier spacing and F _c is the center frequency). 9 shows a permutation matrix 900 and two P matrices 902 (for even k) and 904 (for radix k). In some examples, since half of the subcarriers are muted at any given time during transmission of the LTF from each transmitter, it is possible to boost (eg, 3 dB) the LTF symbols in all transmitter chains. For example, multiplying a vector by P ⁽ k) with even k is equivalent to multiplying a vector by P ^(k) with radix k and reading the result in reverse order (last entry first, first entry last). In some examples, reading in reverse order can be implemented without increasing complexity (eg, using pointer arithmetic and constructing pointers, so data is traversed in the correct order).

As another example, consider the case of order n = 12 (eg, there are 12 antennas). The matrix P ₁₂ 800 shown in Fig. 8 is selected as the base matrix, the time inversion matrix is selected as the permutation matrix, and the P matrix P ^(k) for a given integer k can be defined as follows:

Moreover, the P matrix P ^(k) may be related to the number of subcarriers k. 10 shows a permutation matrix 1000 and two P matrices 1002 (for even k) and 1004 (for radix k). Unlike the previous example, there is an LTF and transmitter chain in which the subcarriers are not muted. For example, for all k, P ^(k) (2,1)=1. This means that the second transmitter chain is never muted for a given subcarrier during the transmission of the first LTF. Thus, for example, there is no need to power boost the signals corresponding to these LTFs and transmitted through these transmitter chains. On the other hand, some subcarriers are muted in the transmitter chain and LTF corresponding to the zero entry of the P matrix. For example, P ⁽¹⁾ (3,4) = 0, whereas P ⁽²⁾ (3,4) = 1. This means that the third transmitter chain will mute half of the subcarriers during transmission of the fourth LTF. Thus, for example, it is possible to boost this LTF by 3dB. Likewise, for a given subcarrier, for example, if the LTF is muted in a given transmitter chain due to a corresponding entry in the P matrix being zero, the LTF may be boosted by 3dB in the transmitter chain.

As another example, consider the case of order n = 10. The matrix P ₁₀ (100) shown in Fig. 1 is selected as the base matrix, and the cyclic shift matrix C ₁₀ ^(k) is selected as the substitution matrix. The P matrix P ^(k) for a given integer k can be defined as:

Note that for a given k, there are only 10 different P matrices, since P ^(k) = P ^(k+10) . 11 shows a substitution matrix 1100 and a P matrix 1102-1120 respectively corresponding to values of k of 0-9.

Furthermore, the P matrix may be associated with P ^(k) subcarriers. Since there is only one K such that, for a given row r and a given column c, P ^(k) (c,r)=0, one tenth of the subcarriers in each LTF in each transmitter chain, is muted Therefore, a power boost of 10 * log 10 (10 / 9) = 0.46 dB may be applied to each of the transmitter chains for all LTFs in some examples. Moreover, the product by the P matrix equals the product by the base matrix followed by a cyclic shift of the result. Thus, in some examples, applying a cyclic shift to a vector can be performed without, for example, a small increase or increase in complexity (e.g., if subcarriers are It can be implemented very efficiently (compared to the case not related to each matrix).

As another example, consider the case of order n = 14. The matrix P ₁₄ (200) shown in Fig. 2 is selected as the base matrix, and the cyclic shift matrix is selected as the permutation matrix. The P matrix P ^(k) for a given integer k can be defined as:

Note that for a given k, there are only 14 different P matrices, since P ^(k) = P ^(k+14) . For each transmitter chain (ie, from each antenna), one-fourteenth of the subcarriers in each LTF are muted (ie, the corresponding element of the corresponding P matrix is zero). Therefore, a power boost of 10 * log 10 (14 / 13) = 0.32 dB may be applied to all transmitter chains in some examples. Moreover, the product by the P matrix equals the product by the base matrix followed by a cyclic shift of the result. Therefore, applying a cyclic shift to a vector can in some examples be implemented very efficiently, often with little or no increase in complexity.

In some examples, transmitting includes transmitting, from each antenna, a symbol from the plurality of subcarriers at a predetermined total transmit power or a maximum aggregate transmit power. This may take into account, for example, any subcarrier that is put due to zero elements in the appropriate positions in the matrix concerned.

Referring again to the methods of methods 500 and 510, in some examples, the plurality of antennas includes at least 10 antennas. Accordingly, the order of the matrix can be at least 10. In some examples, the matrix associated with each antenna comprises a 10x10, 12x12, 14x14, or 16x16 matrix, but an odd order, e.g., a 9x9, 11x11, 13x13 or 15x15 matrix may be used instead.

In some examples, each row and/or column of each matrix associated with a subcarrier includes at least one zero element. This may contribute to a reduction in hardware and/or computational complexity at the transmitter and/or receiver. In some examples, the matrix comprises, for each subcarrier, a symbol transmitted from at least one antenna on that subcarrier is multiplied by a non-zero element, and a symbol transmitted from at least one other antenna on that subcarrier is multiplied by a non-zero element. Zero elements are chosen to be multiplied. In some examples, a row and/or column of each matrix associated with a subcarrier includes at least one complex non-zero element.

에 의해서 규정된 차수 16의 널리 공지된 하다마르(Hadamard) 매트릭스 H₁₆를 고려하는데, 이는 극도로 효율적인 구현을 지원하는 것으로 알려져 있으며, 하드마르 변화니 소정의 곱을 요구하지 않으므로, 동일한 차수의 빠른 푸리에 변환보더 더 효율적이다. H₁₆에 의한 곱을 나타내는 나비 도면(1200)을 도 12에 나타낸다. 이는 128개의 에지를 갖는다. 매트릭스 P₁₆(600)(도 6에 나타냄)에 의한 곱을 나타내는 나비 도면(1300)을 도 13에 나타낸다. 이는 96개의 에지를 갖는다. 그러므로, 매트릭스 P₁₆은 하다마르(Hadamard) 매트릭스보다 상당히 양호한 성능 지수를 갖는다. P₁₆과 동일한 성능 지수를 갖는 또 다른 기본 매트릭스는

인데, H₁₆으로서 크로네커(Kronecker) 프로덕트 구축으로부터 상속된 동일한 대칭들(symmetries)을 갖지만, H₁₆보다 더 많은 제로들을 갖고, 그러므로, P₁₆과 같이 빠른 하다마르 변환보다 더 빠른 프로덕트 알고리즘을 지원한다. 유사하게, 다른 차수의 다른 매트릭스는 동일한 차수의 FFT보다 양호한 성능 지수를 갖는 것으로 나타낼 수 있다. Next, consider the complexity of the calculation of the product by the P matrix. One way to compare the complexity is to draw a plot of the butterfly corresponding to the product by the matrix and use the total number of edges as the figure of merit. A low figure of merit is better than a high figure of merit, as this indicates a lower computational complexity. As a benchmark,

Consider the well-known Hadamard matrix H ₁₆ of order 16 defined by Conversion is more efficient. A butterfly diagram 1200 representing the product by H ₁₆ is shown in FIG. 12 . It has 128 edges. A butterfly plot 1300 representing the product by a matrix P ₁₆ 600 (shown in FIG. 6 ) is shown in FIG. 13 . It has 96 edges. Therefore, the matrix P ₁₆ has a significantly better figure of merit than the Hadamard matrix. Another basic matrix with a figure of merit equal to P ₁₆ is

, which has the same symmetries inherited from the Kronecker product construction as H ₁₆ , but has more zeros than H ₁₆ , and therefore supports a faster product algorithm than the fast Hadamard transform as P ₁₆ . do. Similarly, different matrices of different orders can be represented as having better figure-of-merit than FFTs of the same order.

14 shows a schematic example of an apparatus 1400 for simultaneously transmitting a multicarrier symbol comprising a plurality of subcarriers from a plurality of antennas, wherein each subcarrier is associated with a respective orthogonal matrix. Device 1400 includes processing circuitry 1402 (eg, one or more processors) and memory 1404 in communication with processing circuitry 1402 . Memory 1404 contains instructions executable by processing circuitry 1402 . Device 1400 also includes an interface 1406 in communication with processing circuitry 1402 . Although interface 1406, processing circuitry 1402, and memory 1404 are shown connected in series, they may alternatively be interconnected in some other manner, such as through a burst.

In one embodiment, memory 1404 includes instructions executable by processing circuitry 1402, such that apparatus 1400 is operable to transmit symbols from a plurality of antennas, such that for each antenna: Let the transmitted symbol from each subcarrier be multiplied by the element of each row of the matrix associated with the subcarrier, where the row is associated with the antenna. The matrix is selected such that, from each antenna, symbols transmitted from at least one subcarrier are multiplied by a non-zero element, and symbols transmitted from at least one other subcarrier are multiplied by a zero element. In some examples, apparatus 1400 is operable to perform method 500 described above with reference to FIG. 5A .

15 shows a schematic example of an apparatus 1500 for simultaneously transmitting a multicarrier symbol comprising a plurality of subcarriers from a plurality of antennas, wherein each subcarrier is associated with a respective orthogonal matrix. Apparatus 1500 includes processing circuitry 1502 (eg, one or more processors) and memory 1504 in communication with processing circuitry 1502 . Memory 1504 contains instructions executable by processing circuitry 1502 . Device 1500 also includes an interface 1506 in communication with processing circuitry 1502 . Although interface 1506 , processing circuitry 1502 , and memory 1504 are shown connected in series, they may alternatively be interconnected in some other manner, such as through a burst.

In one embodiment, memory 1504 includes instructions executable by processing circuitry 1502, such that device 1500 is operable to transmit symbols from a plurality of antennas, such that for each antenna: Let the symbol transmitted from each subcarrier be multiplied by an element in each column of the matrix associated with the subcarrier, where the column is associated with an antenna. The matrix is selected such that, from each antenna, symbols transmitted from at least one subcarrier are multiplied by a non-zero element, and symbols transmitted from at least one other subcarrier are multiplied by a zero element. In some examples, apparatus 1500 is operable to perform method 510 described above with reference to FIG. 5B .

It should be understood that the above-mentioned examples are illustrative rather than limiting of the concepts disclosed in this disclosure, and that those skilled in the art will be able to design many alternative embodiments without departing from the appended following remarks. The word "comprising" does not exclude the presence of elements or steps other than those listed in a claim, "a" or "an" does not exclude a plurality, a single processor or other unit being a plurality of units recited in the statement. can perform the function of It should be understood that terms such as “first”, “second” and the like are used only as labels for their special form of conventional identification. In particular, they are to be construed as describing a first or second form of a plurality of such forms (ie, a first or second such form occurring in time or space), unless expressly stated otherwise. The steps of the methods disclosed in this disclosure may be performed in any order unless explicitly stated otherwise. Any reference signs in the statements should not be construed as limiting their scope.

Claims (37)

A method for simultaneously transmitting a multicarrier symbol comprising a plurality of subcarriers from a plurality of antennas, wherein each subcarrier is associated with a respective orthogonal matrix, the method comprising:
transmitting a symbol from the plurality of antennas, wherein, for each antenna, the symbol transmitted from each subcarrier is multiplied by an element in each row of a matrix associated with the subcarrier, wherein the row is an antenna and related;
wherein the matrix is selected such that, from each antenna, symbols transmitted from at least one subcarrier are multiplied by non-zero elements and symbols transmitted from at least one other subcarrier are multiplied by zero elements. According to claim 1,
for each subcarrier, the symbol transmitted from each antenna is multiplied by each element of a column of the matrix associated with the subcarrier. 3. The method of claim 2,
for each subcarrier, the symbol transmitted from each antenna is multiplied by another element of a column of the matrix associated with the subcarrier. A method for simultaneously transmitting a multicarrier symbol comprising a plurality of subcarriers from a plurality of antennas, wherein each subcarrier is associated with a respective orthogonal matrix, the method comprising:
transmitting a symbol from the plurality of antennas, wherein, for each antenna, the symbol transmitted from each subcarrier is multiplied by an element in each column of a matrix associated with the subcarrier, wherein the column comprises an antenna and related;
wherein the matrix is selected such that, from each antenna, symbols transmitted from at least one subcarrier are multiplied by non-zero elements and symbols transmitted from at least one other subcarrier are multiplied by zero elements. 5. The method of claim 4,
for each subcarrier, the symbol transmitted from each antenna is multiplied by each element of the row of the matrix associated with the subcarrier. 6. The method of claim 5,
for each subcarrier, the symbols transmitted from the plurality of antennas are multiplied by each other element in the row of the matrix associated with the subcarrier. According to any one of the preceding claims,
wherein the matrix associated with each subcarrier may be obtained by multiplying a permutation matrix by an orthogonal base matrix or a matrix associated with at least one other subcarrier. According to any one of the preceding claims,
wherein the matrix associated with one of the subcarriers is different from the matrix associated with the at least one other subcarrier. according to any one of the preceding claims,
wherein the first set of subcarriers is associated with a first matrix and the second subset of subcarriers different from the first subset is associated with a second matrix different from the first subset. According to any one of the preceding claims,
wherein transmitting comprises transmitting, from each antenna, a symbol from a plurality of subcarriers at a predetermined total transmit power or a maximum aggregate transmit power. according to any one of the preceding claims,
wherein the plurality of antennas comprises at least 10 antennas. according to any one of the preceding claims,
wherein the matrix associated with each antenna comprises a 10x10, 12x12, 14x14 or 16x16 matrix. according to any one of the preceding claims,
wherein the symbol comprises an OFDM symbol. According to any one of the preceding claims,
wherein the symbol comprises a long training field (LTF). according to any one of the preceding claims,
and each row and/or column of each matrix associated with a subcarrier comprises at least one zero element. according to any one of the preceding claims,
The matrix is such that, for each subcarrier, symbols transmitted from at least one antenna on that subcarrier are multiplied by a non-zero element, and symbols transmitted from at least one other antenna on that subcarrier are multiplied by a zero element. chosen way. A computer program comprising:
17. A computer program comprising instructions that, when executed on at least one processor, cause the at least one processor to perform a method according to any one of claims 1 to 16. As a carrier,
A computer program according to claim 17, comprising:
A carrier is one of an electronic signal, an optical signal, a wireless signal, or a computer readable storage medium. A computer program product comprising a non-transitory computer readable medium storing the computer program according to claim 17 . An apparatus for simultaneously transmitting a multicarrier symbol comprising a plurality of subcarriers from a plurality of antennas, wherein each subcarrier is associated with a respective orthogonal matrix, the apparatus comprising a processor and a memory, the memory comprising: By including commands executable by the device:
operable to transmit symbols from the plurality of antennas, such that, for each antenna, the symbol transmitted from each subcarrier is multiplied by an element in each row of the matrix associated with the subcarrier, wherein the row is associated with the antenna. become;
wherein the matrix is selected such that, from each antenna, symbols transmitted from at least one subcarrier are multiplied by non-zero elements and symbols transmitted from at least one other subcarrier are multiplied by zero elements. 21. The method of claim 20,
The memory includes instructions executable by the processor, the apparatus operable to transmit, for each subcarrier, a symbol from each antenna multiplied by each element of a column of the matrix associated with the subcarrier. 22. The method of claim 21,
The memory comprises instructions executable by the processor, the apparatus operable to transmit, for each subcarrier, a symbol from each antenna multiplied by another element of a column of the matrix associated with the subcarrier. An apparatus for simultaneously transmitting a multicarrier symbol comprising a plurality of subcarriers from a plurality of antennas, wherein each subcarrier is associated with a respective orthogonal matrix, the apparatus comprising a processor and a memory, the memory comprising: By including commands executable by the device:
operable to transmit symbols from the plurality of antennas, such that, for each antenna, a symbol transmitted from each subcarrier is multiplied by an element in each column of the matrix associated with the subcarrier, wherein the column is associated with the antenna. become;
wherein the matrix is selected such that, from each antenna, symbols transmitted from at least one subcarrier are multiplied by non-zero elements and symbols transmitted from at least one other subcarrier are multiplied by zero elements. 24. The method of claim 23,
The memory comprises instructions executable by the processor, the apparatus operable to transmit, for each subcarrier, a symbol from each antenna multiplied by each element of a row of a matrix associated with the subcarrier. 25. The method of claim 24,
The memory includes instructions executable by the processor, the apparatus operable to transmit, for each subcarrier, a symbol from the plurality of antennas multiplied by a different respective element of a row of a matrix associated with the subcarrier. 26. The method according to any one of claims 20 to 25,
wherein the matrix associated with each subcarrier may be obtained by multiplying a permutation matrix by an orthogonal base matrix or a matrix associated with at least one other subcarrier. 27. The method according to any one of claims 20 to 26,
wherein a matrix associated with one of the subcarriers is different from a matrix associated with at least one other subcarrier. 28. The method according to any one of claims 20 to 27,
wherein the first set of subcarriers is associated with a first matrix and the second subset of subcarriers different from the first subset is associated with a second matrix different from the first subset. 29. The method according to any one of claims 20 to 28,
wherein the memory comprises instructions executable by the processor, the apparatus operable to transmit by transmitting, from each antenna, symbols from the plurality of subcarriers at a predetermined aggregate transmit power or a maximum aggregate transmit power. 30. The method according to any one of claims 20 to 29,
wherein the plurality of antennas comprises at least 10 antennas. 31. The method according to any one of claims 20 to 30,
wherein the matrix associated with each antenna comprises a 10x10, 12x12, 14x14 or 16x16 matrix. 32. The method according to any one of claims 20 to 31,
wherein the symbol comprises an OFDM symbol. 33. The method according to any one of claims 20 to 32,
The symbol comprises a long training field (LTF). 34. The method according to any one of claims 20 to 33,
and each row and/or column of each matrix associated with a subcarrier comprises at least one zero element. 35. The method according to any one of claims 20 to 34,
The matrix is such that, for each subcarrier, symbols transmitted from at least one antenna on that subcarrier are multiplied by a non-zero element, and symbols transmitted from at least one other antenna on that subcarrier are multiplied by a zero element. selected device. An apparatus for simultaneously transmitting a multicarrier symbol comprising a plurality of subcarriers from a plurality of antennas, wherein each subcarrier is associated with a respective orthogonal matrix, the apparatus comprising:
operable to transmit symbols from the plurality of antennas, such that, for each antenna, the symbol transmitted from each subcarrier is multiplied by an element in each row of a matrix associated with the subcarrier, wherein the row is the antenna related to;
wherein the matrix is selected such that, from each antenna, symbols transmitted from at least one subcarrier are multiplied by non-zero elements and symbols transmitted from at least one other subcarrier are multiplied by zero elements. An apparatus for simultaneously transmitting a multicarrier symbol comprising a plurality of subcarriers from a plurality of antennas, wherein each subcarrier is associated with a respective orthogonal matrix, the apparatus comprising:
operable to transmit symbols from the plurality of antennas, such that, for each antenna, a symbol transmitted from each subcarrier is multiplied by an element in each column of the matrix associated with the subcarrier, wherein the column is associated with the antenna. become;
wherein the matrix is selected such that, from each antenna, symbols transmitted from at least one subcarrier are multiplied by non-zero elements and symbols transmitted from at least one other subcarrier are multiplied by zero elements.

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